Highly-brominated halogen indigoes and process of making same.



barren Tans PATENT ()FFFICE.

ALBRECHT SUHMIDT, HEINRICH ROSSNER, AND HANS BALIIORN, FHOOHST-ON-THE-MAIN, Gli RMAN Y, ASSIGNORS TO FARBWERKE VORM. MEISTERLUOIUS (KI. BRUNING, OF HOGHST- (IN-'lHE-MAIN, GERMANY, A CORPORATIONOl! GERMANY. I

HIGHLY-BROMINATED HALOGEN INDIGOES AND PROCESS OF MAKING SAME.

Specification of Letters Patent.

Patented April 20, 1909.

Application filed December 17, 1907. Serial No. 406,946.

To all vii/1cm it may concern:

Be it known that we, ALBRECHT SCHMIDT, Rh. ll, l-Imnmon RossNEa, Ph. D.,and HANs BALnionN, Ph. D., chemists, citizens of the Empire of Germany,and residing at Htichst-on-the-Main, Germanyflhave invented certain lmrovements inMaking Highly- Brominated roducts from Dihalogen. Indigoes,of which the following is a specification. We have found that whendibromindigo is stirred with strong sulfuric acid, for instance,sulfuric acid of 85 per cent. strength, concentrated. sulfuric acid,monohydrate and the like, whereby the sulfate of dibroniindigo may beformed, and by then treating the mixture with an excess of more thanfive atoms of broinin in the cold or by gently heating, greenish-blackbromination products are readily obtained which may be separated. fromthe sulfuric acid by filtration. These greenish-black products are to beregarded as perbroniids of brominated indigo dyestuffs; they lose whentreated with agents capable of eliminating bromin, as, for instance, byor on being treatedwit-h hot air, part of the bromin, namely} ltsloosely bound portion When stirred into an iced bisulfite solution theyyield, according to the bromination, a. more or less highly brominated,namely, trior tetra-brominated, indigo dyestuff in a most finely dividedstate. W hen cured on ice, bisulfite and hydrosulfite, owever,grayish-green, in alkali soluble, brominated leuco-compounds areobtained, in the alkaline solution of which cotton and wool are dyedwith a beautiful blue color and according to theolog-ecefifi brominationbeing more greenish-blue as compared with the yet obtained by means ofalkaline reducing agents from the blue parent material.

The bromination in strong sulfuric acid is the stronger and realizableat a lower telnperature the more the acid is concentrated; with asulfuric acid of 85 per cent. strengthat 80 C. the product obtained fromthe green black product of reaction by pouring into bisulfite isessentially a 'tri-brominated indigo dyestull', whereas withconcentrated sulfuric acid at 4050 C. it is a tetra-brominated indigodyestufi'; yet, by means of sul furic acid of 85 per cent. strength at ahigher temperature, for instance at 100 C. may be obtained a green-blackbromination product which after treating with bisullitc represents atetra-brominatcd indigo dycstqfl'. Other di-halogenindigoes, forinstance, di-chlorindigo obtained by chlorinating indigo, have the samereaction.

Example I: 200 parts by weight of di broinindigo, obtained for instance,from indigo by bromination are stirred in a ballmill with 800 parts byWeight of sulfuric acid of 85 per cent. strength whereby gentle heatingmay occur. Then about 200 parts by weight of bromin are allowed to runin at ordinary temperature and stirring is continucd for about 36 hours,preferably while gently heating to about 3040 C. The product of reactionis separated as a greenblack mass. It may be isolated by filtering fromthe sulfuric acid and may be finally pressed between clay or asbestos.It is a green-blackmass having the following propcrties: soluble in muchconcentrated su furic acid with a strong greenish-blue color; whenintroduced into water and a bisulfite solution the green-black massbecomes blue and separates a tri-brominated indigo dyestuff in form ofblueflakes containing about 45 per cent. of bromin. When introduced intoa solution of ice, bisulfite and sodium hydrosulfite a gray-greenishleuco compound is separated soluble in alkali-hydrato with a dark yellowbrown color, dyeing cotton and wool clear blue shades of reddish hue.

Example 115 1 part by weight of di-bromindigo, obtained for instancefrom indigo by brominationis slowly introduced while stirring into 4parts by weight of concen trated sulfuric acid. For the better divisionor conversion into indigo it is preferable to grind in the ball-mill forsome time. 1, 5 parts by weight ofv bromin are then allowed to run inwhile gently cooling and stirring. The temocrature is then preferablyraised while well stirring or grinding in the ballmill to about 45 C.and kept for some hours Stirring is then continued at ordinarytemperature for some further hours. The product of reaction is thenseparated in form of a green-black mass; it may be isolated by filteringfrom the sulfuric acid and finally dried between clay or asbestos. It isa greenislnblaek mass with the following properties: It is soluble inmuch concentrated sulfuric acid with a blue color, introduced into waterand bisulfite solution the product Istufl being separated as blue flakescontain mg about 55 per cent. strength of brominintroduced into asolution of ice, bisulfite and sodium hydrosulfite a gray-greenish leucocompound is separated, soluble in.

alkali-hydrate with a dark yellovv brown color, dyeing cotton and woolclear blue shades.

Example III: 10 parts by weight of chlorinated indigo (German PatentsNos. 168683, 165149, 167830) are stirred in the cold with 40 parts ofconcentrated sulfuric acid and then treated with 1.5 parts of bromin asdescribed in Example I. The greenblack product thus obtained has quitesimilar properties as the product described in Exam le I, and containschlorin and bromin.

Jxample IV: 10 parts by weight of the product of reaction obtained as inExample I by means of concentrated sulfuric. acid are poured into 40partsby weight of a concentrated bisulfite solution to which ice hasbeen added. The dyestufl' separated in blue flakes is'isolated byfiltering. When dry itis a violet-blue powder soluble in concentratedsulfuric acid with a blue color. The product contains about per cent ofbromin and consequently is a tetrabrominated indigo dyestuff.

Example V: 10 parts by weight of the green-black product obtained as inExample II by means of concentrated sulfuric acid, referably byfiltering from the epmess of suluric acid, are introduced while stirringinto an iced solution of 15 parts by weight of sodium hydrosulfite and20 )arts by weight of a concentrated bisulfite so ution. On theevolution of sulfurous acid being complete the gray-greenish leucoproduct" thus obtained is filtered. acid with a dirty olive-green color,in alkalihydrate with a yellow brown color. Wool and cotton are dyed inalkaline solution clear blue shades up Having now described ourinvention, what we claim is:

1. The herein described )IOCGSS of making greenish-black brominateproducts from (ii-halogen indigoes containing at least live atoms ofhalogen, which consists in treating dihalogen-indigosulfate in stronglyconcen trated sulfuric acid with an excess of more than five atoms ofbromin.

2. As new products, the greenisl'i-blaclr. brominated derivatives ofindigo containing at least five atoms of halogen, soluble in muchconcentrated sulfuric acid, turning blue when mixed with water andbisulfite, yielding with hydros'ull ite grayish green. leuco-bodiessoluble in alkali-hydrate.

In testimony, that we claim the foregoing as our invention, we havesigned our names in presence of two subscribing witnesses.

ALBRECHT sornuin'r. HEINRICH ROSSNER. ,HANS BALHORN.

Witnesses:

JEAN GRUND, CARL GRUND.

It is soluble in sulfuric

